/*******************************************************************************
 *   The MIT License (MIT)
 *
 *   Copyright (c) 2014-2017 Marc de Verdelhan, 2017-2018 Ta4j Organization 
 *   & respective authors (see AUTHORS)
 *
 *   Permission is hereby granted, free of charge, to any person obtaining a copy of
 *   this software and associated documentation files (the "Software"), to deal in
 *   the Software without restriction, including without limitation the rights to
 *   use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 *   the Software, and to permit persons to whom the Software is furnished to do so,
 *   subject to the following conditions:
 *
 *   The above copyright notice and this permission notice shall be included in all
 *   copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 *   FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 *   COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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 *   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *******************************************************************************/
package org.ta4j.core;

import org.ta4j.core.num.Num;

import java.io.Serializable;

/**
 * Indicator over a {@link TimeSeries time series}.
 * <p/p>
 * For each index of the time series, returns a value of type <b>T</b>.
 *
 * @param <T> the type of returned value (Double, Boolean, etc.)
 */
public interface Indicator<T> extends Serializable {

    /**
     * @param index the bar index
     * @return the value of the indicator
     */
    T getValue(int index);

	/**
	 * @return the related time series
	 */
	TimeSeries getTimeSeries();

	/**
	 * @return  the {@link Num Num extending class} for the given {@link Number}
	 */
	Num numOf(Number number);

	 /**
	 * Returns all values from an {@link Indicator} as an array of Doubles. The
	 * returned doubles could have a minor loss of precise, if {@link Indicator}
	 * was based on {@link Num Num}.
	 *
	 * @param ref the indicator
	 * @param index the index
	 * @param barCount the barCount
	 * @return array of Doubles within the barCount
	 */
	static Double[] toDouble(Indicator<Num> ref, int index, int barCount) {

		Double[] all = new Double[barCount];

		int startIndex = Math.max(0, index - barCount + 1);
		for (int i = 0; i < barCount; i++) {
			Num number = ref.getValue(i + startIndex);
			all[i] = number.doubleValue();
		}

		return all;
	}

}
